Advanced Materials Research Vols. 374-377

Abstract: A model of rotary wheel combined with heat pump regeneration was presented and an experimental investigation on it was also carried out. Five normal kinds of dehumidification efficiency evaluation standard were introduced in view of the existing various dehumidifying method while the current energy efficiency evaluation indices were analyzed. SMER which defines the dehumidification quantity of unit energy consumption and dehumidification system energy efficiency were introduced and used to compare energy consumption of rotary wheel with or without heat pump. The comparative analysis showed that the system of rotary wheel combined with heat pump regeneration could significantly improve SMER and dehumidification system energy efficiency of rotary wheel.

Abstract: In order to analyze the performance of ejector refrigerator, it is necessary to collect the operation parameters of the system. In this paper, the development of data acquisition(DAQ) system for ejector refrigerator is described. It is based on the technique of visual instrument and the characteristic of ejector refrigerator, using National Instrument’s product LabVIEW. The proposed DAQ system consists of a set of sensors for measuring operating parameters of ejector refrigerator. The collected data are first conditioned using Agilent 34970 data acquisition switch unit and then interfaced to a PC using RS232. The LabVIEW program is used to further process, display and store the collected data in the PC disk. It can realize the real-time data acquisition of temperature, water flow rate and pressure as well as data transmission, processing, and display, in addition to providing users with historic data inquire. The proposed software architecture permits the rapid system development and has the advantage of flexibility and it can be easily altered for application in other refrigeration systems.

Abstract: Qinghai province is one of the important provinces in the development of the western region. It has a continental plateau climate and is extreme cold in winter. There are many local heating modes. Based on the field investigation, this paper presents six heating modes, independent stove, stove Kang, stove heating system, heated Kang, passive solar house, active and passive integration solar house, and compares their advantages and disadvantages. The heating information presented in this paper is significant for the development of heating, and has reference value for heating, ventilation and air conditioning (HVAC) engineers.

Abstract: As a new kind of heat metering and controlling system for central heating system, on-off ratio; on-off valve regulation and household heat allocation technique had been recognized by the scholars recently because of its low cost, simple control process, convenient construction and so on. In China, on-off ratio; on-off valve regulation and household heat allocation technique had been written in “Technical specification for heat metering of district heating system” as a heat metering and controlling system for central heating system and had been applied in some district heating system in China. However, there were some calculated errors if on-off ratio was adopted directly by experiments comparing modified heat metering. There would be a difficulty in charge if ignoring these errors. Due to the circumstance, the applied research of on-off heat metering was carried out in some communities. The measures which on-off ratio was relevantly modified were proposed to improve the heat metering accuracy. On this basis, the method of hourly apportion was put forward to eliminate the adverse effects which the supply/back water temperature had an influence on apportion in different time. By comparison, the accuracy of hourly apportion has a significant improvement compared to accumulate apportion. The preliminary optimized design scheme was acquired to determine the appropriate location of main heat meter according to different cases, and it was significative to optimize the on-off valve regulation and household heat allocation technique. Several problems were found by field information analysis, and the corresponding solutions were obtained by a huge universe of consolidated data and summarize experience. In addition, a few design gists were proposed in the application process of on-off ratio; on-off valve regulation and household heat allocation technique application based on research data.

Abstract: A novel solar-powered hybrid energy system with cooling and heating is presented, which consists of an adsorption ice maker subsystem and water heater subsystem. It can be used as an ice maker and water heater hybrid system or a single water heater respectively according to incident solar radiation intensity. A numerical model is developed to predict the performances of the hybrid energy system. Performance simulation and analysis on the hybrid energy system have been made. Simulation results show that, under the climatic conditions of daily solar radiation being about 12-20MJ/m2, the hybrid energy system can be used as an ice maker and a water heater effectively, its daily solar cooling COP (coefficient of performance) is about 0.173 - 0.181, the daily heating coefficient of performance is about 0.294-0.327.

Abstract: This article uses CFD to study the efficiency of ventilation and pollution discharge of double polluted sources in the lab, and investigate the effect of air exhaust outlet location and air supply velocity on the performance of side ventilation. Using non-dimensional analysis method to analyze change of temperature,velocity with room height, the change of temperature efficiency and pollutants emission efficiency with the air supply velocity. The results show that the efficiencies of temperature and pollutants emission are the highest when h/H=0.175 and v=0.4m/s.

Abstract: Direct Air Cooled Condenser (ACC) has advantages of energy conservation, convenience repair and low production cost. An air-cooled platform structure is designed considering load conditions and the structure’s mechanical characteristics, a finite element model of the ACC platform is set up and static and dynamic analysis are made. The static analysis result shows that the maximum displacement meets the requirements of the structure’s normal use and the industrial equipment’s normal operation; the dynamic analysis result shows that the structure’s overall performance is excellent, the vibration mode of the structure and free period of vibration are reasonable. Based on the model analysis, the quality model, the stiffness model and the relationship between them are discussed.

Abstract: A natural and environment friendly refrigerant propylene and propane are proposed as the substitute of R22 in air conditioner. The experiments were respectively conducted on an existing enthalpy potential lab. Refrigerant charge was held at the constant superheat condition. It is founded that the cooling capacity of R1270 was 96% of R22 system while the R290 was 92% of R22 system, but the COP bother higher than the former system, the refrigerant charge of R1270 was reduced 56.8% of R22 while R290 was 58.4%. With the condensing temperature increased, the system’s cooling capacity is gradually reduced, the cooling capacity of R1270 and R290 are decreased faster than R22, this indicate that R1270 can improve the running performance of system and has more advantages than R290 as substitute for R22, if do some improvement to the original system, can obtain a better results.

Abstract: This design of the ultralow temperature device uses a small cold storage, and the purpose is to study and develop a new environmentally friendly ultralow temperature refrigeration device so that the body temperature could arrival -80 °C. Improvements for the refrigeration system, the use of environmentally friendly refrigerants and the design of refrigerant distribution ratio, and the optimization to the refrigeration system provide a value references, and also make contribution to single-stage compression of non-azeotropic refrigerant to a wide range of applications.

Abstract: This paper presents an energy efficient ventilation method—dam tunnel air handling for hydropower station ventilation. The heat transfer characteristic between supply air and the dam tunnel is studied by model experiment. Supply air velocity, air temperature and dam tunnel surface roughness are chosen as the mainly influencing factors, the air temperature distribution along airflow direction are measured and analyzed in detail. The results show that the heat transfer performance in dam tunnel is improved as the increased of supply air temperature and the dam tunnel surface roughness, or maintained the supply air velocity at a lower level. This experimental study and its results are helpful to develop alternative and efficient systems for hydropower station ventilation.